**4. Types of vertical farms**

#### **4.1 Hydroponics**

It is the predominant growing system used in vertical farms, involving growing plants in nutrient solutions that are devoid of soil. The plant roots are submerged in a nutrient solution, which is frequently examined and circulated to ensure that the correct chemical composition is maintained [12].

**161**

*Implication of Urban Agriculture and Vertical Farming for Future Sustainability*

indoor hydroponics for an improved air quality inside [14].

which is then recycled into the fish tanks [12].

aquaponics to ensure a good source of fresh fish [14].

**4.2 Aquaponics**

**4.3 Aeroponics**

and more nutritious [12].

Urban hydroponics is not a recent invention. The Hanging Gardens of Babylon and the Floating Gardens of the Aztecs were beautifying the cities for quite a long period of time. Also, fruits and vegetables were cultivated in those areas. Nowadays, modern cities use urban hydroponics for physical and psychological relaxation. It is also plays an important role in managing the urban environment. In areas with arid climate, it increases humidity and lowers temperatures. It also captures dust and polluted air by the foliage of the plants. It contributes to the reduction of the overall discharge of CO2, hence preventing global warming to some extent. Hydroponics gardens are usually constructed vertically because city space is limited. Apart from immediate improvement in the environmental quality, vertical farms on top of traditional buildings serve as large heat sinks that radiate heat and increase ambient air temperature; hydroponic systems thermoregulate buildings by trapping heat in the winter and cooling buildings in the summer. The air quality inside the house can also be improved by growing plants on interior walls. In some modern cities, for example in Bangkok, the concrete roads and railway overpasses are covered with hydroponically grown ornamentals. Also commercial centers are decorated with

The hydroponic system is taken one step forward by another system called aquaponics which combines plants and fish in the same ecosystem. The nutrient-rich wastes produced by the indoor-grown fish serve as feed source of the plants present in the vertical farm. On the other hand, the plant filters and purifies the waste water

This combination of systems is cheaper and easier as mineral nutrients are not be purchased and the plants are growing totally organically and moreover no additional expenses are required to clean the fish tanks and there is no scene of pesticides harming the fish. Thus, aquaponics is not only cost-effective but also diseases in the systems can be reduced and a very suitable urban farming technology can be formed. Canadian scientist Savidov explained that possibly the organic components in the system make the trace elements readily available to the plant for proper growth and thus recirculating aquaponic system decreases root diseases in the crop with increased crop yield from aquaponics compared with conventional hydroponics. Also fruits and vegetables grown in aquaponic system qualify for organic product certification very easily since no pesticides and fertilizers are used in this system. Some scientists are planning to construct vertical farms in skyscrapers and have created the name sky farming. Such buildings may also incorporate

This innovative indoor growing technique was first developed by the National Aeronautics and Space Administration (NASA). In the 1990s, NASA started finding efficient ways to grow plants in space and coined the term "aeroponics." Aeroponic systems are still in a growing phase in the vertical farming world, however gaining interest gradually. It is an efficient plant-growing system in vertical farms, using up to 90% less water than other efficient hydroponic systems. Plants grown in these aeroponic systems take up more minerals and vitamins, making the plants healthier

In tropical hot and humid climate, it is difficult to grow temperate vegetables like lettuce. Geoff Wilson, an agricultural journalist and Australia's representative of a group of 16 national organizations for an international Green Roofs

*DOI: http://dx.doi.org/10.5772/intechopen.91133*

*Implication of Urban Agriculture and Vertical Farming for Future Sustainability DOI: http://dx.doi.org/10.5772/intechopen.91133*

Urban hydroponics is not a recent invention. The Hanging Gardens of Babylon and the Floating Gardens of the Aztecs were beautifying the cities for quite a long period of time. Also, fruits and vegetables were cultivated in those areas. Nowadays, modern cities use urban hydroponics for physical and psychological relaxation. It is also plays an important role in managing the urban environment. In areas with arid climate, it increases humidity and lowers temperatures. It also captures dust and polluted air by the foliage of the plants. It contributes to the reduction of the overall discharge of CO2, hence preventing global warming to some extent. Hydroponics gardens are usually constructed vertically because city space is limited. Apart from immediate improvement in the environmental quality, vertical farms on top of traditional buildings serve as large heat sinks that radiate heat and increase ambient air temperature; hydroponic systems thermoregulate buildings by trapping heat in the winter and cooling buildings in the summer. The air quality inside the house can also be improved by growing plants on interior walls. In some modern cities, for example in Bangkok, the concrete roads and railway overpasses are covered with hydroponically grown ornamentals. Also commercial centers are decorated with indoor hydroponics for an improved air quality inside [14].

### **4.2 Aquaponics**

*Urban Horticulture - Necessity of the Future*

safe use of excreta and waste water.

clean product for self-consumption.

light, nutrients, and temperatures.

the Netherlands [13].

**4.1 Hydroponics**

**4. Types of vertical farms**

correct chemical composition is maintained [12].

reduce the rate of the associated health risks.

**3. Vertical farming: an urban farming technology**

1.Reuse of contaminated, untreated irrigation water from urban streams gives rise to potential health risks. This can be managed through complementary health risk reduction measures as explained in the 2006 WHO guidelines for

2.Insufficient or improper management of livestock leads to health risks. Proper management of animals, manure, urine, and slaughterhouse procedures will

3.Intensive use of fertilizers, pesticides, and fungicides in UA may lead to residues of agrochemicals in crops or in the groundwater. The risk mainly occurs in areas with commercial urban farming. In subsistence and semicommercial urban farming, this risk is limited because the producers rarely apply agrochemicals due to poverty. They use composted organic wastes as they prefer a

With rapid worldwide population growth, there is scarcity of agricultural lands. It increases the demand for both more food and more land to grow food. But some entrepreneurs and farmers are beginning to find a solution to this problem, one of which can be found in the abandoned warehouses in our cities, in new buildings built on environmentally damaged lands, and even in used shipping containers from ocean transports. This solution is called vertical farming, which is an UA technology involving growing crops in controlled indoor environments, with precise

In vertical farming, growing plants are arranged in layers that may reach several stories high. Although small-scale, residential vertical gardening (including window farms) is under practice for several years, commercial-scale vertical farms have become an important topic of discussion for the past few years in the United States. This new farming technology is growing rapidly, and entrepreneurs in many

Vertical farming is gaining its importance throughout several urban cities around the world due to the beneficial role it plays in the field of agriculture. Vertical farming can reduce the transportation costs due to its adjacency to the buyer; planned production of herbs and their growing conditions can be enhanced by adjusting the temperature, humidity, lighting conditions, etc. Indoor farming in a controlled environment needs much less amount of water than outdoor farming because it involves recycling of waste water. Because of these features, vertical farming is widely implemented initially in desert and droughtstricken regions, such as some Middle Eastern countries, Africa, Israel, Japan, and

It is the predominant growing system used in vertical farms, involving growing plants in nutrient solutions that are devoid of soil. The plant roots are submerged in a nutrient solution, which is frequently examined and circulated to ensure that the

cities are taking an interest in this innovative farming system [12].

**160**

The hydroponic system is taken one step forward by another system called aquaponics which combines plants and fish in the same ecosystem. The nutrient-rich wastes produced by the indoor-grown fish serve as feed source of the plants present in the vertical farm. On the other hand, the plant filters and purifies the waste water which is then recycled into the fish tanks [12].

This combination of systems is cheaper and easier as mineral nutrients are not be purchased and the plants are growing totally organically and moreover no additional expenses are required to clean the fish tanks and there is no scene of pesticides harming the fish. Thus, aquaponics is not only cost-effective but also diseases in the systems can be reduced and a very suitable urban farming technology can be formed. Canadian scientist Savidov explained that possibly the organic components in the system make the trace elements readily available to the plant for proper growth and thus recirculating aquaponic system decreases root diseases in the crop with increased crop yield from aquaponics compared with conventional hydroponics. Also fruits and vegetables grown in aquaponic system qualify for organic product certification very easily since no pesticides and fertilizers are used in this system. Some scientists are planning to construct vertical farms in skyscrapers and have created the name sky farming. Such buildings may also incorporate aquaponics to ensure a good source of fresh fish [14].

#### **4.3 Aeroponics**

This innovative indoor growing technique was first developed by the National Aeronautics and Space Administration (NASA). In the 1990s, NASA started finding efficient ways to grow plants in space and coined the term "aeroponics." Aeroponic systems are still in a growing phase in the vertical farming world, however gaining interest gradually. It is an efficient plant-growing system in vertical farms, using up to 90% less water than other efficient hydroponic systems. Plants grown in these aeroponic systems take up more minerals and vitamins, making the plants healthier and more nutritious [12].

In tropical hot and humid climate, it is difficult to grow temperate vegetables like lettuce. Geoff Wilson, an agricultural journalist and Australia's representative of a group of 16 national organizations for an international Green Roofs

organization, has reported in an article that a new aeroponic system originated in Singapore can provide a solution to this difficulty. Traditional aeroponic method involved cold nutrient mixture that used to be sprayed onto the plant roots, thereby lowering the temperature causing wilting and ultimately death of the plant. But this type of cooling is expensive, even for rich cities like Singapore. To overcome this limitation, in the year 2004, Gregory Chow, lecturer at the Ngee Ann Polytechnic of Singapore invented the air dynaponics—a much less costly way of maintaining low root-zone temperatures for commercially successful aeroponics. This system gave positive outcomes. Researchers stated that the nutrients infused with oxygen "energized" the entire root system and improved the plant top biomass. Air dynaponics uses the cooling methods of Venturi nozzle effect in an air-powered operation that lowers the temperature of the nutrient mixture and supplies air from the dissolved oxygen. In Singapore, this method is used to produce valuable greens like butterhead lettuce, Batavia lettuce, and Romaine lettuce for moneymaking purposes [14].
